onani

Been to dealer.. been reading 1000 of forum...
been guessing is it the shaft, diff. , heatshield, rotor, brake... got no solution...

Whining niose, whistling noise.. from the rear, if you can let me know what is the problem and where i should check.. would be great...

- Is the noise road speed dependent?
Yes, between 85km/h - 110km/h

- And does it change in pitch as the speed changes?
Noise gone if I step more in throttle or fully release throttle

- Is it independent of the engine speed?
I always hear it when its 85km/h - 110 km/h at sixth gear , reason why must be sixth gear is because if i use 5th gear.. the engine noise will louder than the rear whine noise.

Can you rule out the tranny by putting it into neutral and coasting with the clutch up?
- I tested with neutral and step on the throttle and the noise sounds fine.. there is no whining noise from the rear..

This would define the problem as "downstream" of the tranny.

- Is the noise dependent upon the engine running? Ignition ON? Does it change with rpm? Does it do it while just sitting still and changing rpm?
The noise is from the rear.. not changing with rpm cause if I go neutral and there is no noise.. only when the car is moving at 85km/h..

- Where approx. is the noise coming from? Front, middle, rear?
I definetly hear it from the rear..

- Does it change when you use the service brake from mild to hard? Does it change when you use the ebrake gently? (car moving)
I haven't tested.. I will test it and see...

- Is the noise dependent upon the bumpiness of the road surface?
No.. The noise will only happen at 85km/h - 110km/h on no bumpy road service so you can hear it.. It's not a very noticeable noise.. if you have your top down or turn off the radio you hardly can hear it..

- Does it do it when accelerating, decelerating, coasting.
It does when accelerating slowly from 85km/h to 110km/h what I mean slowly is you step on the throttle probably 1/10 if you step full throttle the noise will not be there.. also when crusing ( using cruise control at a constant speed ) at 85km/h - 110km/h will get a whining noise too from the rear too, but not decelerating or fully release throttle...

- Does it do it more when you are cornering? Left? Right? Hard? Gently?
no..

- Does it do it in reverse?
no...

Recent Service
- Diff. Fluid filled still got niose from the rear..
- Missing bolt on Heatshield fixed still got noise from the rear..

Race Miata

Sounds like the exact same symptom with my S2000 and my miata. I'm pretty sure the noise comes from the rear because the noise didn't go away with my 5-spd to 6-spd box swap in the miata. I also narrowed down the noise to occur when the ring/pinion in the diff are as lightly loaded as possible (i.e. cruising and slight acceleration) at speed. For coasting or clutch in at that speed (85-110km/h), the drag in the tranny will load the ring/pinion enough to make that noise go away. In both cars, there's no leak in the seals. For my S, the diff condition is unknown as I bought the car at ~43k miles (now about ~48k miles) so who knows if the diff is on it's last leg (knock on wood). But with the miata, the ring/pinion were almost brand new and were properly adjusted after the LSD swap and it was still going strong after a great deal of track/autox/street miles.

I don't plan to do anything about the noise except changing the diff fluid frequent enough as it's evident that even the properly aligned healthy miata diff made that noise. That's unless you guys know that it's something big waiting to happen.

onani

Just bring it to the dealer again...

and this is what they told me in the report

"Had Driven car in the specific conditions but stil didn't hear any abnormal noise from the rear. There was slight noise during deceleration as teh ring gear was drivingon the pinion gear inside the differential unit. That's normal due to special design of the hypoid gear. Discussed it with advisor and suggest to recheck later."

Now my question is.. does this make any sense to you guys??

Thanks

oakfloor

It may be the tail shaft bearing in the transmission. theres a thread about this in here somewhere. take a sample of your tranny oil, send it off for a oil analysis. and see if theres bearing metal present. My 00' whines also, and it come from right behind the trannny.

Stratocaster

Translation of what the Dealer said " diff is going bad, but with the parts costing 3000 and labor another 500, we don't want to fix it."

Basicly it is rear gear noise. If you rear is a stock rear end, then it is not normal. That is assuming it is louder then others. Since sound is subjective it is hard to tell if yours is worst then others. There is a small amount of gear noise in our cars stock, just how loud yours is, is the question. Can you cover it up with the radio? Top down, harder to hear then top up? (I assume you can't test this now, it is far too cold where you live)

onani

It's not a very loud noise.. just whistling noise.. or whine... If I turn on my radio or just open some windows there is no way I can hear them.. I will only hear the noise when I am crusing in gear at certain speed and smooth road..

oakfloor

Try this: have it put up on a rack with you in it, put it in gear let the clutch out, have someone listen with a mechanic's stethoscope to find the soruce of noise.

Boostaholic

Sorry to raise this thread from the dead, but did either of you two ever fix/identify this? Or either of you have complete diff failure?

onani

lol Boostaholic .. i still havent fix this stupid noise problem..

I had changed my whole new tranmission..
it doesn't help...

I booked appointment with the dealership next week..

jyeung528

keep us updated.